Got a project that means your Raspberry Pi needs to be outside? Take advantage of solar power to run you Raspberry Pi.
This project by hackitbuildit goes through the steps to add a solar panel to power a Raspberry Pi. The basic concept is to use the Solar panel to charge a 12v battery the Raspberry Pi then takes the power from the battery giving around 5 hours of uasage.
Find out more here Solar-Powered-Raspberry-Pi